A label-free impedimetric strategy using interdigitated electrodes for tetracycline detection in Milk

Area of Science:

• Analytical Chemistry
• Biosensor Technology
• Food Safety Analysis

Background:

• Tetracycline use in livestock leads to residues in dairy products.
• Accurate and robust analytical methods are needed for detecting these residues in complex food matrices.
• Existing methods may require complex sample preparation or lack sensitivity.

Purpose of the Study:

• To develop a label-free, non-enzymatic impedimetric sensor for quantitative tetracycline detection in milk.
• To evaluate the sensor's performance, including its linear range, limits of detection and quantification, accuracy, and matrix tolerance.
• To demonstrate the sensor's practical potential for routine screening of tetracycline residues in dairy products.

Main Methods:

• Fabrication of an impedimetric sensor utilizing interdigitated electrodes (IDEs).
• Electrochemical impedance spectroscopy (EIS) to monitor interfacial charge-transfer processes.
• Nernst-type linearization for quantitative analysis of tetracycline concentrations.

Main Results:

• The IDE-based sensor demonstrated a signal-on response with decreasing charge-transfer resistance as tetracycline concentration increased.
• Achieved a linear detection range of 62.5–1000 nM, with limits of detection and quantification of 2.47 nM and 8.23 nM, respectively.
• Exhibited high accuracy (relative error < 5%) in spiked milk samples, strong matrix tolerance, and good reproducibility and stability.

Conclusions:

• The developed impedimetric sensor is a viable tool for the accurate and sensitive detection of tetracycline residues in milk.
• The sensor's robustness and ease of use make it suitable for routine screening in dairy products.
• This approach offers a practical solution for ensuring the safety of milk and dairy products by monitoring antibiotic residues.